Autogyros, especially permitting the use of these devices as economical airground vehicles

ABSTRACT

Improvements in the rotor system of autogyros permitting the easy folding back of the rotor blades and to ensure the coincidence of the blade axes in a single point. A smooth ball and socket joint housed in the head of a mast supporting the motor is traversed by a shaft about which there is pivoted a member in the form of a cardan fork carrying bearing centered on the axis of rotation and housed in the hub of the rotor, the articulation axes of oscillation of the rotor blades being aligned and mounted in such manner in the hub that they pass through the pivotal center of the unit, the centrifugal force of one of the blades being balanced by that of the other so that no reaction due to these forces is produced on the hub irrespective of the direction of inclination of the rotor.

United States Patent 11 1 DeMontaigu et a1.

11] 3,771,923 1451 Nov. 13, 1973 AUTOGYROS, ESPECIALLY PERMITTING [76]Inventors: Rene Ce'sar Alexandre T assin DeMontaigu, Paris; Ren Stock,Marseille, both of France [22] Filed: Nov. 15, 1971 21 Appl. No.:198,664

[30] Foreign Application Priority Data Nov. 13, 1970 France 7040547 [521US. Cl. 416/143, 416/148 [51] Int. Cl. B64c 27/50 [58] Field of Search416/142, 102, 143,

[56] References Cited UNITED STATES PATENTS 2,631,679 3/1953 Hiller eta1 416/102 X 3,080,002 3/1963 DuPont 416/102 3,087,690 4/1963 Doman eta1. 416/148 3,451,484 6/1969 Sawicki et al 416/148 X 2,105,682 1/1938Bennett et a1.. 416/148 2,464,285 3/1949 Andrews 416/143 UX 2,815,82012/1957 Papadakos 416/143 3,204,700 9/1965 Milligan 416/148 FOREIGNPATENTS OR APPLICATIONS 608,459 9/1948 Great Britain 416/148 419,7804/1947 Italy 4l6/102 Primary Examiner-Everette A. Powell, Jr.Attorney-Karl W. Flocks [57] ABSTRACT Improvements in the rotor systemof autogyros permitting the easy folding back of the rotor blades and toensure the coincidence of the blade axes in a single point.

A smooth ball and socket joint housed in the head of a mast supportingthe motor is traversed by a shaft about which there is pivoted a memberin the form of a cardan fork carrying bearing centered on the axis ofrotation and housed in the hub of the rotor, the articulation axes ofoscillation of the rotor blades being aligned and mounted in such mannerin the hub that they pass through the pivotal center of the unit, thecentrifugal force of one of the blades being balanced by that of theother so that no reaction due to these forces is produced on the hubirrespective of the direction of inclination of the rotor.

6 Claims, 4 Drawing Figures PATENTEUNUY 13 I973 SHEET 3 OF 4 AUTOGYROS,ESPECIALLY PERMITTING THE USE OF THESE DEVICES AS ECONOMICAL AIRGROUNDVESSELS Up to the present time, no success has been achieved in puttinginto operation a practical and economic aero-terrestrial vehicle.However, one of the elements essential to its production exists sincethe perfecting of the autogyro by Juan de la Cierva, the rotor of whichlends itself to an easy and rapid transition from the road vehicleposition to the flying position and vice-versa.

The present invention has for its object on the one hand to permit easyfolding back on themselves of the rotor blades in order that they do notexceed the length of the vehicle and, on the other hand, to makearrangements at the head of the two-blade rotor which, while retainingthe oscillation and drag articulations of the blades by which la Ciervareduced the fatigue in the blades, nevertheless make it possible toensure the coincidence of the blade axes in a single point, irrespectiveof the inclination of the vertical plane to the axis of rotation of therotor (which was not the case with the la Cierva rotor) eliminatingopposing moments and vibrations in the flight controls.

The invention contemplates a folding rotor system of an autogyro whichespecially permits the use of this device as a practical, robust andeconomical air-ground vehicle. This rotor system is characterized inthat a smooth ball and socket joint housed in the head of a supportingmast for the rotor is traversed by a shaft about which there can pivot amember in the form of a cardan fork carrying bearings centered on theaxis of rotation and housed in the hub of the rotor, the axes ofarticulation of the oscillations of the blades being aligned and mountedin such manner in the hub that they pass through the pivotal center ofthe whole unit; the centrifugal forceof one of the blades being balancedby that of the other, no reaction due to these forces takes place on thehub, irrespective of the direction of its inclination.

Vertical supporting pivots rigidly fixed to the fuse Iage are housed inthe folding back articulations of the rotor blades and absorb thetorsion force generated on the basic sections of the blades during thefolding operation.

Other characteristic features and advantages of the present inventionwill be brought out in the description which follows below, referencebeing made to the accompanying drawings, in which:

FIG. 1 is a view-in elevation of an aero-terrestrial vehicle accordingto the invention;

FIG. 2 is a view looking-on the top of the two-blade rotor, one of theblades of which is folded back;

FIG. 3 is a view looking from above and to a larger scale of the hubfitted with attachment stirrups for the blades;

FIG. 4 is a view in vertical cross-section of the rotor hub mounted onthe supporting mast of the machine.

According to the invention, vertical supporting pivots 1 (see FIG. 1)rigidly fixed on the fuselage and engaging in sockets 2 of articulations3 (see FIG. 2) permitting the folding back of the blades, absorb thetorsion force generated on the basic sections 4 of the blades during thefolding operation (see FIG. 2).

In addition, they ensure the support of the blades when folded back inthe road vehicle position. To this end, the supporting pivots I of theblades can be fixed to the fuselage by arms 5 which may be retractableand form a triangulation. Two arms 5 support by their pivot 1 one of thefolded-back blades at the front of the fuselage and the extremity ofthat folded towards therear by a cradle 5a rigidly fixed to these arms,and two other arms 5 support by the other pivot l the other bladefolded-back to the rear of the fuselage and the extremity of that foldedtowards the front by another cradle 5a rigidly fixed to these otherarms.

These arms pivot about axes 6 and can be retracted in the flyingposition. The vertical extremity of the pivots l is conical in order tofacilitate the operation involved in engaging them inside the socket 2of the articulations.

The end sections 7 of the blades may be maintained in the alignment ofthe basic sections 4 in the flying position by means of a pin systempassing into holes 8 fonned in extensions 9 and 10 of these sectionscoupled together by the articulations 3, these holes 8 being placedopposite each other.

This arrangement, permitting the fuselage to absorb the torsion forceacting at the base of a blade which can be folded on itself, when it isfolded back without being retained, may be applied to all cases ofutilization of rotating wings, especially to helicopters in which it isdesired to restrict the space occupied on the ground. It is inparticular possible to contemplate, in the case of a rotating wingsystem of large diameter, the supporting of each portion of the blade tobe folded by a stay supported against the ground.

The rotor system of the machine according to the invention is arrangedat the head of a mast ll fixed and rigidly secured to the machine. Thishead is pierced by an eye 11a serving as a housing for a smooth ball andsocket joint 12 in which is mounted a shaft 13 carrying needle-bearings14 about which oscillates a member 15 serving as a fork. On this forkare mounted, at the upper portion, a bearing 16 supporting an axial loaddirected upwards corresponding to the weight of the whole of the machineduring flight, at the lower portion a bearing 17 in opposition to thebearing 16 carrying the rotor-blades unit when used as a road vehicle.

Two shafts 19 are partly housed in the hub 18 in the case of a mountingwith links of a single piece or alternatively are formed integral withthe hub 18 in the case of a mounting with links in several parts.

Externally to the hub, they constitute the two portions of the samearticulation axis BB for each of the two blades of the rotor. Each bladeis mounted as a hinge on this pivotal axis and comprises at its base astirrup P having two links 20 and one link 21. The link 21 of onestirrup is arranged between the two links 20 of the other (see- FIGS. 3and 4).

A split conical sleeve ensures the absence of play and tightening iseffected by means of rings 22 of needlebearings, with the aid ofa nut 23locked by any conventional locking means.

A positioning stud 12a, arranged radially, prevents the ball and socketjointfrom moving about the axis of rotation of the hub under the effectof the frictional forces of the bearings.

The whole unit is operated angularly by a member 24 on which are mounteda bearing 25 and an operating lever 26. The base of the part 24oscillates about the center of the ball and socket joint driving in itsmovements a floating member 27 which slides on an antitorque cradle 28rigidly fixed to the mast.

The launching of the rotor is effected by a pinion 29 sliding inside acasing 30 and coming into engagement with a toothed wheel 31 of the hub18. The driving torque is transmitted by a shaft 32 and ajoint 33.Braking is effected by means of brake-shoes 34 in frictional contactwith the interior of the ring 31 forming a brakedrum.

The rotor hub device for a rotating wing system according to theinvention makes possible, in spite of the presence of an individualoscillation articulation for each blade, the coincidence of the axes ofarticulation of the hub and the blades at a single point 0, irrespectiveof the direction of the axis of rotation of the rotor and the angle oflift of the blades, so that the resultant of all the static and dynamicforces, especially those due to angular acceleration or centrifugalforces, passes through the center of the rotor, thus avoiding any momentwith respect to this center which could be a generator of vibration andinstability during rotation and during evolutions in course of flight.

The invention offers the same advantages as with rigid blades fixed inrespect of oscillations. The fixed portion is only required to withstandthe forces corresponding to the driving torque for launching or thosedue to braking. During auto-rotation, the forces are extremely small ascompared with the centrifugal force.

The control of inclination of the blades is effected in such manner asto coexist, in the best aerodynamic position, with the launching deviceof the rotor, whether it is mechanical or hydraulic with one or withseveral driving pinions.

It will of course be understood that the present invention has only beendescribed and illustrated by way of a preferred example, and equivalentsmay be employed in its constituent elements without thereby departingfrom the scope of the said invention as defined in the appended claims.

We claim:

1. Rotor system of the autogyro type, especially permitting the use of amachine as an air-groud vehicle which is practical, robust andeconomical, said system comprising in combination a mast supporting arotor member and including a head portion formed with an eyelet in whichis disposed a smooth ball and socket joint, said ball and socket jointbeing traversed by a shaft, a cardan fork member supported on said shaftin pivotal relationship thereabout, said cardan fork carry ing bearingsdisposed in concentric relationship with the axis of rotation of saidrotor member, said bearings also being housed within a hub portion ofsaid rotor member whereby rotor blades may be mounted on said hubportion with the articulation axes of oscillation thereof aligned insuch manner that they pass through the pivotal center of said system sothat centrifugal force of one blade will balance that of the other withthe result that no reaction due to these forces would be produced on thehub portion irrespective of the direction of inclination of the rotormember.

2. Rotor system in accordance with claim 1, charac terized in that twoshafts partly housed in the hub portion constitute externally of thesaid hub portion the two portions of a single axis of articulation ofoscillation for each of the two blades of the rotor member, each bladebeing mounted as a hinge on the said articulation axis and comprising atits base a stirrup with links complementary to the links of the stirrupof the other blade.

3. Rotor system in accordance with claim 1, characterized in that aninclination control acts on a cradle which can move in the longitudinaland transverse di' rection around the center of the rotor member, afloating member permitting these 2 of freedom, while preventing angulardisplacement about the axis of rotation and thus forming an anti-torqueto the moment of the mechanical launching and braking, this slidingmember moving over a base fixed on the mast rigidly attached to themachine.

4. Rotor system in accordance with claim 3, characterized in that theinclination control of the said rotor is effected in such manner as tocoexist, in the best aerodynamic position, with the launching device ofthe rotor, whether this is mechanical or hydraulic, with one only orseveral driving pinions.

5. Rotor system in accordance with claim 1, characterized in thatvertical pivot supports are fixed in the articulations for folding backthe blades and absorb the torsion force generated on the base sectionsof the blades during the folding operation.

6. Rotor system in accordance with claim 5, characterized in that thepivot supports are fixed to the fuselage of the machine by arms forminga triangulation and being retractable if so desired. a: a: a:

1. Rotor system of the autogyro type, especially permitting the use of amachine as an air-groud vehicle which is practical, robust andeconomical, said system comprising in combination a mast supporting arotor member and including a head portion formed with an eyelet in whichis disposed a smooth ball and socket joint, said ball and socket jointbeing traversed by a shaft, a cardan fork member supported on said shaftin pivotal relationship thereabout, said cardan fork carrying bearingsdisposed in concentric relationship with the axis of rotation of saidrotor member, said bearings also being housed within a hub portion ofsaid rotor member whereby rotor blades may be mounted on said hubportion with the articulation axes of oscillation thereof aligned insuch manner that they pass through the pivotal center of said system sothat centrifugal force of one blade will balance that of the other withthe result that no reaction due to these forces would be produced on thehub portion irrespective of the direction of inclination of the rotormember.
 2. Rotor system in accordance with claim 1, characterized inthat two shafts partly housed in the hub portion constitute externallyof the said hub portion the two portions of a single axis ofarticulation of oscillation for each of the two blades of the rotormember, each blade being mounted as a hinge on the said articulationaxis and comprising at its base a stirrup with links complementary tothe links of the stirrup of the other blade.
 3. Rotor system inaccordance with claim 1, characterized in that an inclination controlacts on a cradle which can move in the longitudinal and transversedirection around the center of the rotor member, a floating memBerpermitting these 2* of freedom, while preventing angular displacementabout the axis of rotation and thus forming an anti-torque to the momentof the mechanical launching and braking, this sliding member moving overa base fixed on the mast rigidly attached to the machine.
 4. Rotorsystem in accordance with claim 3, characterized in that the inclinationcontrol of the said rotor is effected in such manner as to coexist, inthe best aerodynamic position, with the launching device of the rotor,whether this is mechanical or hydraulic, with one only or severaldriving pinions.
 5. Rotor system in accordance with claim 1,characterized in that vertical pivot supports are fixed in thearticulations for folding back the blades and absorb the torsion forcegenerated on the base sections of the blades during the foldingoperation.
 6. Rotor system in accordance with claim 5, characterized inthat the pivot supports are fixed to the fuselage of the machine by armsforming a triangulation and being retractable if so desired.